Valve for servo-steering devices

ABSTRACT

A HYDRAULIC VALVE FOR A SERVO STEERING DEVICE WHERE THE HYDRAULIC FLUID FLOWS THROUGH A CONTINUOUS LONGITUDINAL SLOT IN THE STEERING SHAFT. THE RELATIVE POSITION OF AN ENVELOPING SLEEVE WILL CONTROL THE APPROPRIATE FLOW OF HYDRAULIC FLUID TO EFFECTUATE THE ROTARY MOVEMENT. A SPINDLE CONNECTED TO THE STEERING SHAFT INCLUDES INTERNAL TEETH THAT ENGAGE IN THE SAME CAVITY FORMED BY THE CONTINUOUS SLOTS LOCATED IN THE STEERING SHAFT. THIS PARTICULAR HYDRAULIC CONDUIT SYSTEM ELIMINATES THE COSTLY MACHINING ASSOCIATED WITH OTHER HYDRAULIC SYSTEMS.

United States Patent Enrique Carbo Mengual 1/1967 Eddy.

[72] Inventor 1/1967 Eddy et a1..

10/1968 Primary Examiner-Henry T. Klinksiek 1 [22] Sept. 19, 1969 [45]Patented June 28, 1971 Attorney-Sughrue, Rothwell, Mion, Zinn andMacPeak [54] VALVE FOR SERVO-STEERING DEVICES 3 Claims, 2 Drawing Figs.[52] U S Cl ABSTRACT: A hydraulic valve for a servo steering devicewhere the hydraulic fluid flows through a continuous longitudinal slotin the steering shaft. The relative position of an enveloping sleevewill control the appropriate flow of hydraulic fluid to effectuate therotary movement. A spindle connected that engage in the 137/625.2l Fl6k11/02 [50] Field of 91/374- References Cited UNITED STATES PATENTS8/1964 Vickerseta1.................

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to the steering shaft includes internal teeth same cavity fonned by thecontinuous slots located in the hydraulic conduit system sociated withother hydrausteering shaft. This particular 3,145,626 137/625.24Xeliminates the costly machining as 3,227,178 1/1966E1wel1.......................... 137/625.2l lic systems.

' directions, through the enveloping sleeve of the steering shaftconnected to the spindle, takes place through some continuous slots cutinto the, shaft. According to the relative positions of the sleeve andshaft, as the latter turns, certain communications of the mechanism areset up to regulate the hydraulic circulation, in such a way that theinternal teeth of the spindle body engage in the same cavity resultingfrom the aforementioned continuous slots forits rotary drive.

Optionally the sliding sleeve may be fitted with a freely adjustablecentering device which comprises an eccentric pivot connected to acylindrical body which is fixed to the base of the spindle, of a lesshard nature, by means of peripheral knurling which is pressed into andembedded in the base.

Optionally also, the distance ratio between the guide rings and thediameter of the rotor sleeve is optimal with the eccentric pivotsituated between both rings.

Other aims and features of the invention will be further described indetail in the following specification with reference to the accompanyingdrawings, in which:

FIG. 1 is a longitudinal section of a servo steering device fitted withthe members according to the invention;

FIG. 2 is a cross section of the mechanism of the previous FlG., takenacross the line 11-.

The servo steering mechanism is lodged in a housing 1 connected to thecasing 2 which contains the steering bar 3 fitted with a toothed segment4, the teeth 5 of which engage with further teeth 6 of a slide 7. inturn, this slide 7 cooperates with a spindle 8 through balls 9 which runin a helical slot 10 cut into the spindle itself, with a return passagethrough some in ternal conduits 11.

The slide 7 is fitted with a front shield 12 and separates chambers 13and 14 in which the fluid exerts servo steering operative pressureeffects.

The spindle 8 is related to the steering shaft 15, which shaft iscontrolled by the manually operated steering wheel holding steeringcolumn, by way of axial teeth 16. Also, the shaft 8 is in fixedcooperation with a torsion bar 17, concentrically housed in the shaftlS,by way ofa pin 18.

The torsion bar 17 is also fixed to the shaft by way of a further pin 19housed at the opposite end of the connection of the torsion bar 17 tothe spindle 8.

The servo steering mechanism control valve comprises essentially asleeve 20 which surrounds the shaft 15, having bores 21, 22 and aperipheral groove 23, and slots 24 and 25. These bores, grooves andslots establish sporadic communication with inlet and outlet ports 27and 28 respectively, as well as with a passage 29 which communicateswith the chamber 14 through a tubular member 30 mounted between thehousing 1 and easing 2 by way of adjusting nuts 31.

The sleeve 20 has guide rings 32 and 33, sealing rings 34 and acentering device. This latter device comprises a member 35 with anoffset pivot 36, which may be positionally adjusted by way of knurling37 which enables this member 35 to be embedded under pressure in thebase of the spindle which is of a softer nature; for possible removal ofthe member 35, it is equipped with a threaded orifice 38 allowing forthe introduction of a threaded pin for extraction purposes.

The teeth 16 of the spindle 8 penetrate into the slots 25 of the shaft15; further axial slots 41 cooperate with the slots and bores of thesleeve 20. The slots 25 of the shaft 15 comprise the essence of theinvention, since they are characterized by being continuous, that is,they are developed all along the zone of facing between the shaft andthe sleeve 20 and with the internal drivin teeth 16 of the spindle 8.

The advantage t at the continuous slot 25 indubitably offers proceedsfrom its ease of machining, contrary to what happens in similarmechanisms in which the same slots are broken down into other smallerones which are difficult and time consuming to work. The continuousnature of the slots 25 is feasible because of the uniformity ofpressures shown by the fluid in the diverse areas communicated by thesame slots. The cross section 40 of the slots 25 is optimal for theirhydraulic and mechanical function.

The mechanism is completed by a ring 43 with bore 44 and bearings anddiverse accessories. These bearings are the following: two axialbearings 45 and 46 situated at both sides of a peripheral flange 47 ofthe base of the spindle 8 and a further radial bearing 48 situatedaround the same base. The casing 2 has a rear cover 50 held in place byscrews 51 and equipped with a toric joint 52.

The servo steering mechanism operates as follows. In the stable positionwhich the torsion bar 17 tends to communicate to the mechanism, the oilenters through port 27 and through the bore 21 reaches slot 41 of shaft15 from where it can find its way out direct to port 28.

When an attempt is made to turn the steering, the steering efforts ismomentarily contained by the torsion bar 17 and when the opposition ofthe latter is overcome, the steering mechanism starts to work to developthe convenient turn; the limit of this turn is controlled by theposition in which slots 25 of the shaft run up against the teeth 16 ofthe spindle.

Thus, when the shaft 15 turns, the slots 41 of said shaft are displacedwith respect to those of the sleeve 20, in such a way that the oil findsa way through the passage 29 and tubular member 30 towards the chamber14 where it exerts a pressure which causes movement of the slide 7. Atthe same time, the oil held without pressure in the other chamber 13 isdriven out through a bore 44 towards the outlet.

The contrary direction of turn for the steering is obtained in thereverse way.

I claim:

1. A hydraulic valve for servo steering devices comprising a steeringshaft having at least one continuous longitudinal slot capable oftransmitting hydraulic fluid; a spindle having internal teethoperatively connected to the steering shaft, at least one internal toothengaging one continuous slot for rotary operation; and an envelopingsleeve that, according to its relative position to the steering shaft,is capable of regulating the flow of hydraulic fluid, whereby thecontinuous slot in the shaft is capable of transmitting hydraulic fluidregardless of the relative rotation of the enveloping sleeve.

